Occlusal hypofunction induces atrophic changes in rat gingiva.
OBJECTIVE
To clarify the influence of occlusal hypofunction on the integrity of gingival tissue and gingival extracellular matrix biosynthesis.


METHODS
Thirteen-week-old male Wistar rats were divided into two groups. To eliminate occlusal forces, all the right maxillary molars were extracted in the hypofunctional group. The control group was anesthetized but not subjected to surgery. The rats were killed at 2 and 4 weeks after the procedure, and the lower right second molars were prepared for histological analysis. To investigate the effect of occlusal hypofunction on collagen biosynthesis, the expression of connective tissue growth factor (CTGF) and lysyl oxidase (LOX) was determined by immunohistochemistry as well as histological examination by hematoxylin and eosin staining.


RESULTS
Disorientation of the collagen fibers, proliferation of the connective tissue fibroblasts, and enlargement of epithelial intercellular gaps were observed in gingival tissue of rat molars with experimental occlusal hypofunction. Immunohistochemically, the expression of CTGF and LOX was increased significantly (P < .05) in the hypofunctional group.


CONCLUSIONS
These results suggest that occlusal hypofunction can affect the structural integrity and the expression of CTGF and LOX in gingival tissue.
Ishida
Yuji
Y
Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. yjis.orts@tmd.ac.jp
Kanno
Zuisei
Z
Soma
Kunimichi
K
D000818:Animals; D001732:Bite Force; D049109:Cell Proliferation; D003094:Collagen / Q000096:biosynthesis; D055513:Connective Tissue Growth Factor / Q000032:analysis; D004847:Epithelial Cells / Q000473:pathology; D005109:Extracellular Matrix / Q000378:metabolism; D005110:Extracellular Space; D005347:Fibroblasts / Q000473:pathology; D005881:Gingiva / Q000473:pathology; D005882:Gingival Diseases / Q000209:etiology*; D007150:Immunohistochemistry; D008297:Male; D008310:Malocclusion / Q000150:complications*; D008437:Maxilla; D008963:Molar / Q000601:surgery; D055093:Periodontal Atrophy / Q000209:etiology*; D008249:Protein-Lysine 6-Oxidase / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D014081:Tooth Extraction
D055513:Connective Tissue Growth Factor; D003094:Collagen; D008249:Protein-Lysine 6-Oxidase